Browsing by Author "Koziol, Krzysztof K. K."
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Item Open Access 4D printing of materials for the future: opportunities and challenges(Elsevier, 2019-10-16) Joshi, Siddharth; Rawat, Krishna; Karunakaran, C.; Rajamohan, Vasudevan; Mathew, Arun Tom; Koziol, Krzysztof K. K.; Kumar Thakur, Vijay; Balan, A.S.SThe concept of 4D printing is its formation of complex three-dimensional structures that have the ability to adopt different shapes and forms when subjected to different environmental stimuli. A few researchers simply view 4D printing as an extended technique of 3D printing or additive manufacturing with the added constraint of time. However, the unique shape change mechanism exhibited in this process is a combination of shape programming and the usage of smart active materials mostly polymers. This review article highlights the various smart materials, activation mechanisms and the shape-changing techniques employed in the 4D printing process. The potential of the shape-changing structures and their current applications in various biomedical and engineering fields is also explored. The article aims to emphasize the potential and viability of 4D printing and focused on providing an in-depth insight into the 4D printing process.Item Open Access 4D printing of smart polymer nanocomposites: integrating graphene and acrylate based shape memory polymers(MDPI, 2021-10-24) Chowdhury, Jaydeep; Anirudh, Premnath Vijay; Karunakaran, Chandrasekaran; Rajmohan, Vasudevan; Mathew, Arun Tom; Koziol, Krzysztof K. K.; Alsanie, Walaa F.; Kannan, Chidambaram; Balan, Arunachalam S. S.; Thakur, Vijay KumarThe ever-increasing demand for materials to have superior properties and satisfy functions in the field of soft robotics and beyond has resulted in the advent of the new field of four-dimensional (4D) printing. The ability of these materials to respond to various stimuli inspires novel applications and opens several research possibilities. In this work, we report on the 4D printing of one such Shape Memory Polymer (SMP) tBA-co-DEGDA (tert-Butyl Acrylate with diethylene glycol diacrylate). The novelty lies in establishing the relationship between the various characteristic properties (tensile stress, surface roughness, recovery time, strain fixity, and glass transition temperature) concerning the fact that the print parameters of the laser pulse frequency and print speed are governed in the micro-stereolithography (Micro SLA) method. It is found that the sample printed with a speed of 90 mm/s and 110 pulses/s possessed the best batch of properties, with shape fixity percentages of about 86.3% and recovery times as low as 6.95 s. The samples built using the optimal parameters are further subjected to the addition of graphene nanoparticles, which further enhances all the mechanical and surface properties. It has been observed that the addition of 0.3 wt.% of graphene nanoparticles provides the best results.Item Open Access Advancing the use of high-performance graphene-based multimodal polymer nanocomposite at scale(MDPI, 2018-11-17) Ahmad, Ibrahim A.; Koziol, Krzysztof K. K.; Deveci, Suleyman; Kim, Hyun-Kyung; Kumar, Ramachandran VasantThe production of an innovative, high-performance graphene-based polymer nanocomposite using cost-effective techniques was pursued in this study. Well-dispersed and uniformly distributed graphene platelets within a polymer matrix, with strong interfacial bonding between the platelets and the matrix, provided an optimal nanocomposite system for industrial interest. This study reports on the reinforcement of high molecular weight multimodal-high-density polyethylene reinforced by a microwave-induced plasma graphene, using melt intercalation. The tailored process included designing a suitable screw configuration, paired with coordinating extruder conditions and blending techniques. This enabled the polymer to sufficiently degrade, predominantly through thermomechanical-degradation, as well as thermo-oxidative degradation, which subsequently created a suitable medium for the graphene sheets to disperse readily and distribute evenly within the polymer matrix. Different microscopy techniques were employed to prove the effectiveness. This was then qualitatively assessed by Raman spectroscopy, X-ray diffraction, rheology, mechanical testing, density measurements, thermal expansion, and thermogravimetric analysis, confirming both the originality as well as the effectiveness of the process.Item Open Access Biomimetically inspired highly homogeneous hydrophilization of graphene with poly (L-DOPA): toward electroconductive coatings from water-processable paints(American Chemical Society, 2022-05-10) Kuziel, Anna; Dzido, Grzegorz; Jędrysiak, Rafał G.; Kolanowska, Anna; Jóźwiak, Bertrand; Beunat, Juliette; Korczeniewski, Emil; Zięba, Monika; Terzyk, Artur P.; Yahya, Noorhana; Thakur, Vijay Kumar; Koziol, Krzysztof K. K.; Boncel, SławomirWater-based processing of graphene─typically considered as physicochemically incompatible with water in the macroscale─emerges as the key challenge among the central postulates of green nanotechnology. These problematic concerns are derived from the complex nature of graphene in the family of sp2-carbon nanoallotropes. Indeed, nanomaterials hidden under the common “graphene” signboard are very rich in morphological and physicochemical variants. In this work, inspired by the adhesion chemistry of mussel biomaterials, we have synthesized novel, water-processable graphene–polylevodopa (PDOPA) hybrids. Graphene and PDOPA were covalently amalgamated via the “growth-from” polymerization of l-DOPA (l-3,4-dihydroxyphenylalanine) monomer in air, yielding homogeneously PDOPA-coated (23 wt %) (of thickness 10–20 nm) hydrophilic flakes. The hybrids formed >1 year stable and water-processable aqueous dispersions and further conveniently processable paints of viscosity 0.4 Pa·s at 20 s–1 and a low yield stress τ0 up to 0.12 Pa, hence exhibiting long shelf-life stability and lacking sagging after application. Demonstrating their applicability, we have found them as surfactant-like nanoparticles stabilizing the larger, pristine graphene agglomerates in water in the optimized graphene/graphene–PDOPA weight ratio of 9:1. These characteristics enabled the manufacture of conveniently paintable coatings of low surface resistivity of 1.9 kΩ sq–1 (0.21 Ω·m) which, in turn, emerge as potentially applicable in textronics, radar-absorbing materials, or electromagnetic interference shielding.Item Open Access Carbon nanotube films spun from a gas phase reactor for manufacturing carbon nanotube film/carbon fibre epoxy hybrid composites for electrical applications(Elsevier, 2019-09-06) Chen, Jinhu; Lekawa-Raus, Agnieszka; Trevarthen, James; Gizewski, Tomasz; Lukawski, Damian; Hazra, Kalyan; Rahatekar, Sameer S.; Koziol, Krzysztof K. K.Working towards improvement of the electrical performance of carbon fibre (CF) reinforced polymer composites used in aircrafts, we have developed new routes of production of hybrid carbon nanotube (CNT)/CF epoxy composites. It was shown that the use of CNT films produced via one-step chemical vapour deposition (CVD) based method and in-process control of films morphology combined with standard vacuum bagging based manufacture of the composites results in very good electrical performance of the final material, delivering high potential for lightning strike related applications including electromagnetic interference (EMI) shielding and static dissipation for the composite components used in aerospace and transport sector. Simultaneously, the process is much simpler, inexpensive and easy to upscale than previously proposed methods.Item Open Access Carbon nanotubes and graphene radiant heater printed on a cementitious flooring substrate: a feasibility study(SSRN, 2020-10-26) Patsavellas, John; Salonitis, Konstantinos; Koziol, Krzysztof K. K.; Zakrzewski, Lukasz; Blackwood, BenThe human activity of heating homes contributes a significant amount of CO2 in the total of the UK Green House Gases and the process of retrofitting residential stock and equipping new dwellings with lower and carbon neutral technologies could be complex, costly and physically challenging. This paper investigates the feasibility of a composite mixture of carbon nanotubes (CNT) and graphene material applied as a printed layer to the underside of a cementitious flooring substrate, acting as a radiant underfloor heater. Screening sample tests confirm instant radiant heating at low DC voltages with remarkably low conduction heat losses through the substrate.Item Open Access Comparative life cycle assessment of aluminium and CFRP composites: the case of aerospace manufacturing(Springer, 2024-02-24) Atescan Yuksek, Yagmur; Mills, Andrew; Ayre, David; Koziol, Krzysztof K. K.; Salonitis, KonstantinosAs climate change intensifies and existing resources are depleted, the need for sustainable industries becomes more important. The aviation industry is actively addressing environmental concerns by enhancing fuel efficiency and adopting lighter materials, especially carbon fibre composites. Research has proven that the use of carbon fibre composites provides cumulative benefits in reducing fuel consumption over the entire life cycle of an aircraft. However, existing studies are lack of a comprehensive exploration of the diverse impacts associated with composite manufacturing processes and recycling methods. To address this gap, a comparative life cycle assessment analysis covering the materials’ manufacturing, operation, and end-of-life phases is conducted. This analysis includes aluminium alloy and five different carbon fibre composite materials produced with varied constituents and manufacturing methods. Composite manufacturing processes, encompassing carbon fibre production, resin selection, and composite manufacturing methods, are considered. Weight savings based on the mechanical properties of utilised composite type are also taken into account. Results highlight the potential to mitigate the environmental impact of composite materials through strategic choices in constituent types, manufacturing processes, and disposal scenarios. Moreover, break-even distances indicate that aluminium becomes more environmentally detrimental than the analysed composite structures beyond a flight distance of 300,000 km.Item Open Access Conductive inks of graphitic nanoparticles from a sustainable carbon feedstock(Elsevier, 2016-09-22) Hof, Ferdinand; Kampioti, Katerina; Huang, Kai; Jaillet, Christèle; Derré, Alain; Poulin, Philippe; Yusof, Hisham; White, Thomas; Koziol, Krzysztof K. K.; Paukner, Catharina; Pénicaud, AlainMicrowave plasma splitting of biogas to solid carbon forms is a promising technique to produce large quantities of sustainable carbon based nano materials. Well defined graphitic nano carbons have been produced exhibiting graphene multilayers in turbostratic packing. After heat treatment, the purified material has been used to formulate stable, aqueous dispersions. These dispersions are used directly as inks, allowing the preparation of conductive membranes with remarkable resistivity. Nano carbons derived by plasma processes constitute a promising alternative to carbon black because they can be prepared from renewable sources of methane or natural gas, are calibrated in size, exhibit high conductivity, and have promising perspectives for chemical and material science purposes.Item Open Access Copper-decorated CNTs as a possible electrode material in supercapacitors(MDPI, 2019-09-03) Ciszewski, Mateusz; Janas, Dawid; Koziol, Krzysztof K. K.Copper is probably one of the most important metal used in the broad range of electronic applications. It has been developed for many decades, and so it is very hard to make any further advances in its electrical and thermal performance by simply changing the manufacture to even more oxygen-free conditions. Carbon nanotubes (CNTs) due to their excellent electrical, thermal and mechanical properties seem like an ideal component to produce Cu-CNT composites of superior electrochemical performance. In this report we present whether Cu-CNT contact has a beneficial influence for manufacturing of a new type of carbon-based supercapacitor with embedded copper particles. The prepared electrode material was examined in symmetric cell configuration. The specific capacity and cyclability of composite were compared to parent CNT and oxidized CNT.Item Open Access Development of hybrid electrospun alginate-pulverized moringa composites(Royal Society of Chemistry, 2024-03-12) Orisawayi, Abimbola Oluwatayo; Koziol, Krzysztof K. K.; Hao, Shuai; Tiwari, Shivam; Rahatekar, Sameer S.The consideration of biopolymers with natural products offers promising and effective materials with intrinsic and extrinsic properties that are utilized in several applications. Electrospinning is a method known for its unique and efficient performance in developing polymer-based nanofibers with tunable and diverse properties presented as good surface area, morphology, porosity, and fiber diameters during fabrication. In this work, we have developed an electrospun sodium alginate (SA) incorporated with pulverized Moringa oleifera seed powder (PMO) as a potential natural biosorbent material for water treatment applications. The developed fibers when observed using a scanning electron microscope (SEM), presented pure sodium alginate with smooth fiber (SAF) characteristics of an average diameter of about 515.09 nm (±114.33). Addition of pulverized Moringa oleifera at 0.5%, 2%, 4%, 6%, and 8% (w/w) reduces the fiber diameter to an average of about 240 nm with a few spindle-like pulverized Moringa oleifera particles beads of 300 nm (±77.97) 0.5% particle size and 110 nm (±32.19) with the clear observation of rougher spindle-like pulverized Moringa oleifera particle beads of 680 nm (±131.77) at 8% of alginate/Moringa oleifera fiber (AMF). The results from the rheology presented characteristic shear-thinning or pseudoplastic behaviour with a decline in viscosity, with characteristic behaviour as the shear rate increases, indicative of an ideal polymer solution suitable for the spinning process. Fourier transform infrared spectroscopy (FT-IR) shows the presence of amine and amide functional groups are prevalent on the alginate-impregnated moringa with water stability nanofibers and thermogravimetric analysis (TGA) with change in degradation properties in a clear indication and successful incorporation of the Moringa oleifera in the electrospun fiber. The key findings from this study position nanofibers as sustainable composites fiber for potential applications in water treatment, especifically heavy metal adsorption.Item Open Access The effect of the gaseous environment on the electrical conductivity of multi-walled carbon nanotube films over a wide temperature range(MDPI, 2020-01-21) Janas, Dawid; Koziol, Krzysztof K. K.The surrounding gas atmosphere can have a significant influence on the electrical properties of multi-walled carbon nanotube (CNT) ensembles. In this study, we subjected CNT films to various gaseous environments or vacuum to observe how such factors alter the electrical resistance of networks at high temperatures. We showed that the removal of adsorbed water and other contaminants from the surface under reduced pressure significantly affects the electrical conductivity of the material. We also demonstrated that exposing the CNT films to the hydrogen atmosphere (as compared to a selection of gases of inert and oxidizing character) at elevated temperatures results in a notable reduction of electrical resistance. We believe that the observed sensitivity of the electrical properties of the CNT films to hydrogen or vacuum at elevated temperatures could be of practical importance.Item Open Access Extreme magneto-transport of bulk carbon nanotubes in sorted electronic concentrations and aligned high performance fiber(Nature Publishing Group, 2017-09-22) Bulmer, John S.; Lekawa-Raus, Agnieszka; Rickel, Dwight G.; Balakirev, Fedor F.; Koziol, Krzysztof K. K.We explored high-field (60T) magneto-resistance (MR) with two carbon nanotube (CNT) material classes: (1) unaligned single-wall CNTs (SWCNT) films with controlled metallic SWCNT concentrations and doping degree and (2) CNT fiber with aligned, long-length microstructure. All unaligned SWCNT films showed localized hopping transport where high-field MR saturation definitively supports spin polarization instead of a more prevalent wave function shrinking mechanism. Nitric acid exposure induced an insulator to metal transition and reduced the positive MR component. Aligned CNT fiber, already on the metal side of the insulator to metal transition, had positive MR without saturation and was assigned to classical MR involving electronic mobility. Subtracting high-field fits from the aligned fiber's MR yielded an unconfounded negative MR, which was assigned to weak localization. It is concluded that fluctuation induced tunnelling, an extrinsic transport model accounting for most of the aligned fiber's room temperature resistance, appears to lack MR field dependence.Item Open Access Gas physisorption measurements as a quality control tool for the properties of graphene/graphite powders(Elsevier, 2020-06-08) Marchesini, Sofia; Turner, Piers; Paton, Keith R.; Reed, Benjamen P.; Brennan, Barry; Koziol, Krzysztof K. K.; Pollard, Andrew J.The industrial-scale production and commercialisation of graphene and related 2D materials introduces the need for rapid, reliable and cost-effective quality control procedures. Currently, microscopy-based techniques are used to measure the lateral size and thickness of particles but while powerful, these techniques suffer from limitations such as lengthy analysis time, high costs and limited sampling. In the case of carbon-based 2D materials, as the stacking of multiple graphene sheets causes a reduction in the surface to mass ratio, the number of layers can hypothetically be calculated by comparing the theoretical surface area of monolayer graphene (2630 m2/g) to the calculated specific surface area (SSA) measured by gas physisorption measurements. However, despite the potential of this method of analysis, there is limited understanding regarding the characterisation of commercial graphene/graphite powders produced via bottom-up and top-down methods. Herein, the SSAs of a variety of commercially-available graphitic powders were measured using nitrogen physisorption isotherms at 77 K and applying Brunauer-Emmett-Teller theory. The as-obtained SSAs were then correlated to the structural and chemical properties of the materials (obtained using conventional techniques) to demonstrate the suitability of this measurement technique for quality control of graphitic powdersItem Open Access The operational window of carbon nanotube electrical wires treated with strong acids and oxidants(Nature Publishing Group, 2018-09-25) Lepak-Kuc, Sandra; Boncel, S.; Szybowicz, M.; Nowicka, A. B.; Jozwik, I.; Orlinski, K.; Gizewski, T.; Koziol, Krzysztof K. K.; Jakubowska, M.; Lekawa-Raus, A.Conventional metal wires suffer from a significant degradation or complete failure in their electrical performance, when subjected to harsh oxidizing environments, however wires constructed from Carbon Nanotubes (CNTs) have been found to actually improve in their electrical performance when subjected to these environments. These opposing reactions may provide new and interesting applications for CNT wires. Yet, before attempting to move to any real-world harsh environment applications, for the CNT wires, it is essential that this area of their operation be thoroughly examined. To investigate this, CNT wires were treated with multiple combinations of the strongest acids and halogens. The wires were then subjected to conductivity measurements, current carrying capacity tests, as well as Raman, microscopy and thermogravimetric analysis to enable the identification of both the limits of oxidative conductivity boosting and the onset of physical damage to the wires. These experiments have led to two main conclusions. Firstly, that CNT wires may operate effectively in harsh oxidizing environments where metal wires would easily fail and secondly, that the highest conductivity increase of the CNT wires can be achieved through a process of annealing, acetone and HCl purification followed by either H2O2 and HClO4 or Br2 treatment.Item Open Access Photonic sorting of aligned, crystalline carbon nanotube textiles(Nature Publishing Group, 2017-10-11) Bulmer, John S.; Gspann, Thurid S.; Orozco, Francisco; Sparkes, Martin; Koerner, Hilmar; Di Bernardo, A.; Niemiec, Arkadiusz; Robinson, J. W. A.; Koziol, Krzysztof K. K.; Elliott, James A.; O’Neill, WilliamFloating catalyst chemical vapor deposition uniquely generates aligned carbon nanotube (CNT) textiles with individual CNT lengths magnitudes longer than competing processes, though hindered by impurities and intrinsic/extrinsic defects. We present a photonic-based post-process, particularly suited for these textiles, that selectively removes defective CNTs and other carbons not forming a threshold thermal pathway. In this method, a large diameter laser beam rasters across the surface of a partly aligned CNT textile in air, suspended from its ends. This results in brilliant, localized oxidation, where remaining material is an optically transparent film comprised of few-walled CNTs with profound and unique improvement in microstructure alignment and crystallinity. Raman spectroscopy shows substantial D peak suppression while preserving radial breathing modes. This increases the undoped, specific electrical conductivity at least an order of magnitude to beyond that of single-crystal graphite. Cryogenic conductivity measurements indicate intrinsic transport enhancement, opposed to simply removing nonconductive carbons/residual catalyst.Item Open Access The true amphipathic nature of graphene flakes: a versatile 2D stabilizer(Wiley, 2020-07-16) Kuziel, Anna W.; Milowska, Karolina Z.; Chau, Pak‐Lee; Boncel, Slawomir; Koziol, Krzysztof K. K.The fundamental colloidal properties of pristine graphene flakes remain incompletely understood, with conflicting reports about their chemical character, hindering potential applications that could exploit the extraordinary electronic, thermal, and mechanical properties of graphene. Here, the true amphipathic nature of pristine graphene flakes is demonstrated through wet‐chemistry testing, optical microscopy, electron microscopy, and density functional theory, molecular dynamics, and Monte Carlo calculations, and it is shown how this fact paves the way for the formation of ultrastable water/oil emulsions. In contrast to commonly used graphene oxide flakes, pristine graphene flakes possess well‐defined hydrophobic and hydrophilic regions: the basal plane and edges, respectively, the interplay of which allows small flakes to be utilized as stabilizers with an amphipathic strength that depends on the edge‐to‐surface ratio. The interactions between flakes can be also controlled by varying the oil‐to‐water ratio. In addition, it is predicted that graphene flakes can be efficiently used as a new‐generation stabilizer that is active under high pressure, high temperature, and in saline solutions, greatly enhancing the efficiency and functionality of applications based on this material